Pressure-operated bottom-hole drill stem tester



.packers set near the bottom of ythe hole.

United States Patent @ffice 2,830,667 Patented Apr. 15, 1958 PRESSURE-OPERATED ABOTTQM-HOLE LDRILL .STEM TESTER John fE..Walstrom, Grinda, Calif., assigner, by mesne assignments, to California Research Corporation, San Francisco, Calif., a corporation of Delaware Application N ovemberl 16, 1954,`=Serial No. 469,179

The present invention relates to apparatus for withdrawing Huid samples from earth formations traversed by a bore hole, more particularly to apparatus for sampling uid content of a formation through the bottom of a bore hole and has foren objectthe provision of an rimproved apparatus for open-hole sampling in situ of .the iluids contained ,in earth Aformations lying at the bottom of the .bore hole by providing means forsealing `the end face .of the bodymember into engagement with the-bottom `of the Vbore `hole in response-to an increase in the vertical thrustron the body member, thereby sealing an entrance port means extending through the end face into engagement .with the bottom land further controlling `the thrust on the body member to open valve meansy to permit communication-between the entrance port and the interior ofthe drill pipe upon `which the body member is `supported while relieving the hydrostatic head `on the bottom of the bore so that iiuid within the formation at the bottom of the bore hole may rise inthe drill pipe.

During the drilling of wells for oil, gas, and the like,

it is often desirable to be able to test the fluid content of formations'lying directly at the bottom of the bore hole.

`Such testing is often done upon obtaining an oill or `gas show in the drilling fluid or cuttings that are continuously received by returning the circulation of the fluid stream to the earths surface. Heretofore, drill stem-'testing of'itluid content lying directly` at the bottom is normally accomplished only by pulling the drill pipe and running a drill stem testing tool, utilizing one or more full-hole sidewall In deep holes it is often not feasible to runjfull-hole packers to the bottom of thehole due to the small clearance that exists between these packers and the sides of the hole, and due to `other operating diiculties. In such an instance it becomes necessary to` pull the drill pipe `out of thehole, I

put on a smaller-size bit, drill ahead in a small-size hole, remove the drill pipe and run a drill stem tester equipped with one or more reduced-size sidewall packers to lit the reduced hole; or a cone packer to seat on the shoulder at the top of the reduced-size hole. However, this latter type of formation fluid testing operation is extremely costly due to the necessity of stopping the normal drilling operation to drill a reduced-diameter hole, and subsequently requiring opening of the hole to -its full-hole size again. Additionally, boring ahead into the formation to establish. the reduced-size hole may result in passage entirely througha potentially productive oil zone `into a water zone, shale, `or other uninteresting formation.

determine `the fluid content of earth formations lying directly ahead in a bore hole, which may be used at any time duringthe drilling of a well without departure from conventional full-size hole drilling procedures, and without requiring use of conventional sidewall packers and their restricted clearances. Further, the formation fluid content is sampled in ,adequate volume to obtaina true representation of the i'luid in accordance with the invention by supporting the testing apparatus at the lower end of a ,string ofconventionalrdrill pipe.

In carryingout the invention, a body membery is provided with means .extending along the lower end of the ybody for sealing the lower end face portion of the .body intoengagement with :the .bottom of the bore hole by controlling the verticalthrust on the body member against thebottom of the bore hole. The sealing means, ,in a preferred form of the apparatus, is initially stretched land held in .tension over the lower end of the `body member, and port means are provided which open through that portion ,of said sealing means forming the end face of the tester body. As the body member is brought into engagement with the bottom of the bore hole and the vertical' thrust increased by permitting the weight of the .drill pipe to relieve the initial tension on said sealing means, -the body of the tester is securely sealed into firm engagement with the .bottom of the bore hole.

Further, in accordancewith the invention, an increased vertical thrust on the body member actuates a Valve means provided 4intermediate the port means through the sealed end face of the body member and the interior of the `drill pipe so that after said sealing means has become engaged with the bottom of the bore hole, the hydrostatic pressure on ythe .earth formation exposed to the bottom of the lbore hole may be relieved, thereby permitting the pressure of fluids in the formation to cause a sample of the connate fluids to risel in the dn'll stem. A pressureequalizingvalve means is provided to equalize the pressure between that portion of the entrance port means in engagement with the earth formation exposed through the end face and the pressure of drilling duid adjacent the bottom of the well bore after the rst valve has been closed byV relieving the thrust on the tester body so that said tester body, the drill pipe, and the fluid contained therein may be withdrawn from the Well and examined as to contents.

Further objects and advantages of the present invention will become apparent from the following detailed description taken in conjunction with the accompanying drawing, which forms an integral part of the present specification.

In the drawing:

Fig. l is a diagrammatic representation of a preferred form of the present invention illustrating the testing tool being lowered into a full-diameter well bore and just prior to the setting of the end packing means.

Fig. 2 is a View similar to Fig. l, illustrating the body member of the testing apparatus in its seated position,

.with the main valve means opened for communication Vpermit closing of the end of the drill stem tester and `opening of the auxiliary valve means to equalize the pressure between the bottom of the bore hole and Hthe interior `of the port means through which uid content v,of the formation has been sampled.

Referring now .to the drawing,` there is illustrated in Figs. l, 2 and 3 the sequence of operating steps performed by a preferred form of apparatus for carrying out the tool is covered by an end packing means 17 which extends along and around the lower end of the body member forming the testing tool. In the arrangement of Fig. 1, port means, formed by pipe 16, extends axially ahead of and through packing means 17, and may include a drill surface, formed by depositing diamond dust in the end 19 of pipe 16. Pipe 16 is secured to cup mem ber 36 by collar 37 and set screw 38 so that it will rotate with cup member 36. Member 36 in turn is rotatable by body member 10 through the key ways formed in lip 39 of member 36 and keys 40 secured to outer sleeve 20. Thus, by rotation of body member 10 through drill pipe 11. a firm seating of the packer means 17 against the bottom of the bore hole .14 may be assured by drilling pipe i 16 a short distance into formation 18.

In the preferred construction of end packing means 17, there is provided means for initially biasing the resilient packing material, which may be formed of rubber, so that said packer means will be stretched to assume the form shown in Fig. l. This may be accomplished by compressing a helically coiled spring member 21, formed of spring steel or the like, Within the rubber'packer means and maintaining the compression during the molding and curing of the rubber. After curing, the spring is relieved so that the packer 17 will assume the configuration illustrated in Fig. l and, through its own resilience, may be fitted to engage closely the lower end of the body member 10. The originally molded condition of the packer means 17 is thus obtained when the spring means 21 is relieved, by permitting the weight of drill pipe 11 to compress coil spring 29 and thereby permit spring 21 to relieve packer 17 to the condition illustrated in Fig. 2. As there shown, packer means 17 is preferably molded to the lowervend of sleeve 20 forming the outside of body 10 and has a slightly more enlarged diameter than sleeve 20 to increase the area of contact between the lower end of testing tool 10 and the bottom of the bore hole. It

will be seen that by the increased thrust, by permitting more of the weight of the drill pipe 11 to rest on the body of tester tool 10, spring 21 may be compressed and the resilience of packer 17 permitted to operate to expand the packer into engagement with bottom 14 of bore hole 12.

With the packer means 17 thus firmly engaged with the bottom of the bore hole and pipe or port means 16 in communication with the formation 18, lying directly at the bottom of the bore hole, the valve means, identified as 22, is opened to bring the port means into communication with the interior of chamber 24 formed by drill pipe 11. In the arrangement of the present embodiment, valve means 22 includes a plurality of ports 23 formed in the upper end of pipe 16, which may be brought into communication with the ports 25 in the downwardly extending inner sleeve member 27. As shown, valve means 22 is likewise operated by an additional thrust on body member 10, causing compression of coil spring 29 and the shearing of shear pin 30, which holds the valve member closed against -the differential hydrostatic pressure created by the difference in drilling fluid pressure on the outside of testing tool 10 and the atmospheric or reduced pressure on the inside. As mentioned above, coil spring 29 also aids in the stretching of packer 17 to its originally elongated condition. i

After the opening of valve 22 and a predeterminable time for the influx of fluid from formation 18, valve means 22 may be closed by lifting the weight of drill pipe 11 to relieve the compressional force on spring 29 to permit it to return to the position illustrated in Fig. 3.

Immediately thereafter, the downward thrust on end sealing means 17 is relieved by permitting integral spring 21 to force packing means 17 into its originally elongated or deformed condition. In order to permit testing tool 10 to be withdrawn from bottom 14 of well bore 12, there is provided an auxiliary valve means formed by ports 32 and 33 for pressure relief between the interior of port means 16 and the bottom of the Well bore due to the hydrostatic head exerted by drilling fluid remaining in the well bore. To this end, port 32 in sleeve 20 is permitted to communicate with a similar port 33 in the telescoping sleeve or cup member 36. This position of ports 32 and 33 is normally blocked during running in of the tool to its formation testing position by shear pin 30. Accordingly, with relief of vertical thrust on tool 10, ports 32 and 33 permit drilling fluid to enter the interior of the entrance port, pipe 16, through slots 23 formed in the upper part thereof. Thus, with the pressure equalized between the interior and exterior of the lower end of the testing tool and with valve means 22 closed to its original position, with formation fluid trapped therein, drill string 11 and testing tool 10 may be removed from the bore hole and the fluid entrapped within chamber 24 of pipe 11 examined for uid content.

From the foregoing description, it will be seen that in accordance with the present invention an apparatus has been provided for testing formations lying at the bottom of a full-size bore hole, wherein a packer means seals the lower end of'the body member of the testing tool into firm engagement with the bottom by control of the vertical thrust on the tester body by regulation of the vertical load of drill pipe applied thereto. The apparatus is furthercharacterized by there being provided an initially deformed packer means extending along and around the lower end of said tool for sealing against the hydrostatic pressure on the formation at the bottom of the well bore by being relieved of its deforming load, valve means for opening the interior of said body to admit fluid and for closing the lower end of said body member to entrap formation fluid within the body of the testing tool and the drill pipe upon which the body member is supported, and pressure equalizing valve means, operable when the main valve recloses, to permit ready removal of the tool from the bo're hole, after said packer means has again been deformed by relief of its load.

Various modifications and changes in the foregoing apparatus will occur to those skilled in the art from the foregoing detailed description. All such modifications and changes falling within the scope of the appended claims are intended to be included therein.

I claim:

l. Open-hole formation testing apparatus for determining the fluid content of an earth formation at the bottom of a full diameter bore hole comprising a body member adapted to be supported by a drill pipe extending from said body member to the earths surface, said body member having a diameter substantially smaller than that of said bore hole in which it is to be employed, deformable packer means extending across a substantial portion of the lower end face of said body member and extending vertically along the side walls of said body member, a pipe member of substantially smaller diameter than said body member extending into said body member through said end face and through said packer means, means for inserting said pipe member into the earth formation at the bottom of said well bore, means for sealing said packer means against the bottom of said bore hole and around said pipe member including spring means within and bonded to a resilient material forming the body of said packer means, said spring means being biased to place said deformable material under an initial tension along the side walls of said body member so that upon lcompression of said packer means the spring bias is relieved to permit said resilient Amaterialof said packer means to ow` more:readilyEintoaengagement with the bottom of said bore hole while ymaintaining sealing engagement with thev side walls of said body member,rmeans for longitudinally compressingthe `side walls .of said` packer means when said end face is seated on bottom, valve means interconnecting the upper end of said pipe member and the interior of said drill pipe, said valve means being operable upon the application of a predeterminable vertical movement after said packer means has been compressed into sealing engagement with the bottom of said well bore, and means for closing said valve means after exposure of the interior of said drill pipe to the earth formation penetrated by said pipe member to entrap formation fluid within said drill pipe.

2. Apparatus for sampling the fluid content of an earth formation lying directly at the bottom of a well bore comprising a body member adapted to be supported at the lower end of a length of drill pipe extending to the earths surface, said body member having an outer sleeve member forming the outside wall of said body member, said sleeve member having a diameter substantially smaller than that of the well hole, a deformable packer for the lower end of said body member having side walls extending upwardly along the side of said body member and the upper end of said wall secured to the lower end of said outer sleeve member, a cup member forming the bottom of said body member slidably receivable within said outer sleeve, an inlet pipe member having its upper end closed extending through the lower portion of said packer means and through the bottom portion of said cup member, said pipe being secured to said cup member, an inner sleeve member adapted to receive the closed upper end of said pipe member, the upper walls of said pipe member and the lower end of said inner sleeve member having mating port means formed therein to permit communication between the upper end of said pipe member and the interior of said inner sleeve member, spring means for initially biasing said cup member and said pipe member away from both said inner and outer sleeve members to maintain said port means out of registration, means including the weight of the drill pipe for relieving the initial bias on said spri-ng means to open said port means between said pipe member and the interior of said body member and the lower end of the supporting drill pipe, the last-named means being adapted to deform simultaneously the side walls of said packer means to permit flow of the resilient material of said packer means against irregularities of the bottom of the bore hole, and valve means for relieving the difference in hydrostatic head between the bottom of the well bore and said earth formation after a sample of the well fluid has been taken, comprising port members formed in the side wall of said outer sleeve and in the side wall of said t cup member, said port means in said outer sleeve and said cup being adapted to be brought into registry by removal of weight of said cup member through said spring means.

3. Open hole formation testing apparatus for obtaining a uid sample of an earth formation at the bottom of a well bore comprising a sample chamber adapted to be supported at the lower end of a length of drill pipe extending to the earths surface, said chamber having a diameter substantially less than that of said well bore and its interior open to said drill pipe, an outer sleeve member secured to the lower end of said sample chamber, an inner sleeve member having an inner bore communicating with the lower end of said drill pipe through said sample chamber, a cup member slidably received between said inner and outer sleeve members forming a bottom closure for said sample chamber, said cup member including a pipe member whose lower end is adapted to be brought into engagement with an earth formation lying directly at L theY bottom of the well bore, spring means for initially maintaining said cup member and said pipe mem- `ber axially biased away from said sleeve members, the upper end `of'said pipe member being closed to prevent free communication `with the interior of said inner sleeve member, port meansformed between the upper side walls of said pipe member and the lower end of said inner sleeve to permit fluid flow between said pipe member and said sample chamber, packing means surrounding the lower end of said cup member and having its upper end secured to the lower end of said outer sleeve member, said packing means being formed of resilient material -having included therein spring biasing means bonded thereto for maintaining said resilient material under tension when assembled on the lower end of said cup member, and means including the weight of said sample chamber and said drill pipe for relieving the internal spring bias on said packer means to permit the lower end `of said packer means to conform into sealing engagement with the bottom of the well bore, said means being further operable to relieve the initial spring bias on said cup member to permit entry of said pipe member into the interior of said inner sleeve and permit free fluid ow under reduced hydrostatic head from said earth formation through said port means in said pipe member and said inner sleeve into said sample chamber and the drill plpe.

4. Apparatus for testing the dynamic uid ow characteristic of an earth formation lying directly ahead of the bottom of a full diameter well borewithout requiring the drilling of a reduced diameter borehole into said formation under test which comprises means for supporting a tester body member as an integral part of the lower end of a string of empty drill pipe extending from said body member to the earths surface, both said tester body and said drill pipe having substantially uniform diameter throughout a major portion of their lengths and being substantially smaller in diameter than the well bore in which they are used, said tester body having a fluid receiving chamber in free communication with the interior of said empty drill pipe so that fluid entering said chamber may rise unrestrictedly in said pipe, deformable packer means extending across a substantial portion of the lower end of said body member and extending vertically along the side walls of said body member, a pipe member forming an entrance port means for said body member of substantially smaller diameter than said body member and extending from said body member through said end face and through said packer means, means including said drill pipe for rotating said pipe member to drill it into engagement with the earth formation and to seat said deformable packer means on the bottom of said well bore, coil spring means extending vertically along the outer side walls of said body member and secured to said packer means for additionally deforming said packer means into sealing engagement with the bottom of said well bore, valve means formed by ports in the upper end of said pipe member, mating port means formed in the lower end of a sleeve member slidably receiving said pipe member, said mating port means being in communication with the fluid-receiving chamber of said tester body, valve spring means for initially biasing the support member for said pipe member away from said sleeve member to maintain said port means out of registration, means including the weight of the drill pipe for relieving the initial bias on said spring means to bring said port means into registration after said deformable packer means has been seated on bottom, and pressurerelief valve means for equalizing the difference in a hydrostatic pressure between the interior of said sample chamber in contact with the earth formation and borehole outside of said deformable packer means after a sample of the formation uid has been taken, said pres- 7 sure-relief valve means comprising port means formed in References Cited in the file of this patent the side wall of said tester body and corresponding port UNITED STATES PATENTS means formed in said support member for said pipe mem- 7 t p ber, said relief valve means being adapted to be brought 2 1711000 Ide v Aug- 29' 1939 into registry upon removal of the weight of said drill pipe 5 2,626,777 True Jan 27' 1953 from said tester body and said valve spring means. 2'637400 grown et al May 5 1953 

1. OPEN-HOLE FORMATION TESTING APPARATUS FOR DETERMINING THE FLUID CONTENT OF AN EARTH FORMATION AT THE BOTTOM OF A FULL DIAMETER BORE HOLE COMPRISING A BODY MEMBER ADAPTED TO BE SUPPORTED BY A DRILL PIPE EXTENDING FROM SAID BODY MEMBER TO THE EARTH''S SURFACE, SAID BODY MEMBER HAVING A DIAMETER SUBSTANTIALLY SMALLER THAN THAT OF SAID BORE HOLE IN WHICH IT IS TO BE EMPLOYED, DEFORMABLE PACKER MEANS EXTENDING ACROSS A SUBSTANTIAL PORTION OF THE LOWER END FACE OF SAID BODY MEMBER, A VERTICALLY ALONG THE SIDE WALLS OF SAID BODY MEMBER, A PIPE MEMBER OF SUBSTANTIALLY SMALLER DIAMETER THAN SAID BODY MEMBER EXTENDING INTO SAID PACKER MEANS, MEANS FOR SAID END FACE AND THROUGH SAID PACKER MEANS, MEANS FOR INSERTING SAID PIPE MEMBER INTO THE EARTH FORMATION AT THE BOTTOM OF SAID WELL BORE, MEANS FOR DEALING SAID PACKER MEANS AGAINST THE BOTTOM OF SAID BORE HOLE AND AROUND SAID PIPE MEMBER INCLUDING SPRING MEANS WITHIN AND BONDED TO A RESILIENT MATERIAL FORMING THE BODY OF SAID PACKER MEANS, SAID SPRING MEANS BEING BIASED TO PLACE SAID DEFORMABLE MATERIAL UNDER AN INITIAL TENSION ALONG THE SIDE WALLS OF SAID BODY MEMBER SO THAT UPON COMPRESSION OF SAID PACKER MEANS THE SPRING BIAS IS RE- 